While GPS-enabled devices for navigation out of doors is common, GPS signals do not penetrate into interior spaces. Accordingly, other systems and methods are typically used.
For example, it is well known to use a laser range finder, echo locator or other devices that emit a signal, such as an electromagnetic or sound, by which distances to other objects in the room may be calculated.
Yet other systems comprise a gyroscope or similar inertial measurement device to determine the position of the object. Still another system relates to using a wheel attached to an odometer to measure distance. Both system types typically measure distance relative to a past point at which the object was located.
Systems existing for navigating toward a landmarks are also known. However, these systems typically require accurate knowledge of the three-dimensional position of the various landmarks and stable recognition of the landmark in the navigation process.